Blackened optical component without fluorescence

Abstract

An optical component may be optically blackened so that the surface of the component is not reflective when light impinges upon the surface. In some examples, a method of blackening involves exposing a surface of the optical component that defines an optical pathway to an optical blackening composition for a period of time effective to optically blacken the surface. The optical blackening composition may be configured so that the resulting optically blackened optical pathway is non-fluorescing when exposed to ultraviolet light. In some examples, the optical blackening composition comprises selenous acid and is devoid of organic molecules.

The invention claimed is: 
     
       1. A method of blackening an optical component comprising:
 exposing a surface of an optical component that defines an optical pathway to an optical blackening composition that comprises selenous acid for a period of time effective to optically blacken the surface and yield an optically blackened optical pathway that is non-fluorescing; 
 removing residual optical blackening composition from the surface of the optical component; and 
 drying the optical component. 
 
     
     
       2. The method of  claim 1 , wherein the optical pathway is non-fluorescing such that the surface defining the optically blackened pathway does not emit fluorescent emissions when exposed to ultraviolet light. 
     
     
       3. The method of  claim 1 , wherein the optical pathway is non-fluorescing such that the surface defining the optically blackened pathway does not emit fluorescent emissions when exposed to light within a range from 250 nm to 600 nm. 
     
     
       4. The method of  claim 1 , wherein the optical blackening composition is devoid of organic dyes. 
     
     
       5. The method of  claim 1 , wherein seleneous acid ranges from 0.05 volume percent to 1 volume percent of the optical blackening composition and greater than 80 volume percent water. 
     
     
       6. The method of  claim 5 , wherein exposing the surface of the optical component to the optical blackening composition comprising selenous acid comprises:
 exposing the surface of the optical component to a first concentration of selenous acid; 
 removing residual selenous acid at the first concentration from the surface; and 
 subsequently exposing the surface of the optical component to a second concentration of selenous acid greater than the first concentration. 
 
     
     
       7. The method of  claim 6 , wherein exposing the surface of the optical component to the first concentration of selenous acid comprises exposing the surface of the optical component to the first concentration of selenous acid for an amount of time longer than the surface of the optical component is exposed to the second concentration of selenous acid. 
     
     
       8. The method of  claim 6 , wherein the first concentration of selenous acid ranges from 0.1 volume percent to 0.4 volume percent of the optical blackening composition, and the second concentration of selenous acid ranges from 0.15 volume percent to 0.6 volume percent of the optical blackening composition. 
     
     
       9. The method of  claim 1 , wherein the optical blackening composition comprises a transition metal. 
     
     
       10. The method of  claim 9 , wherein the transition metal is copper ranging from 0.1 to 3 volume percent of the optical blackening composition. 
     
     
       11. The method of  claim 1 , wherein:
 exposing the surface of the optical component to the optical blackening composition comprises immersing the optical component the optical blackening composition, 
 removing residual optical blackening composition from the surface of the optical component comprises rinsing the surface of the optical component with water, and 
 drying the optical component comprises drying at a temperature ranging from 250 degrees Fahrenheit to 1350 degrees Fahrenheit. 
 
     
     
       12. The method of  claim 1 , wherein the period of time ranges from 30 seconds to five minutes. 
     
     
       13. The method of  claim 1 , further comprising, prior to exposing the surface of the optical component to the optical blackening composition, cleaning the surface with phosphoric acid. 
     
     
       14. The method of  claim 1 , wherein the optical component is fabricated from aluminum or stainless steel. 
     
     
       15. The method of  claim 1 , wherein the optical component is a housing for an optical sensor that defines an opening for an optical emitter and an opening for an optical detector, wherein the optical pathway is arranged to direct light from the optical emitter through an optical window optically connected to the optical pathway into a fluid sample under analysis and receive light from the fluid sample through the optical window and direct the light to the optical detector. 
     
     
       16. An optical component comprising:
 a surface formed of metal that defines an optical pathway configured to receive light from a fluid sample under analysis through an optical lens, 
 wherein the surface is optically blackened with a metal selenide and does not emit fluorescent emissions in response to being exposed to ultraviolet light. 
 
     
     
       17. The optical component of  claim 16 , wherein the metal is copper and the optical component is fabricated from aluminum or stainless steel. 
     
     
       18. The optical component of  claim 16 , wherein the surface is not anodized and is devoid of a coating containing organic molecules. 
     
     
       19. The optical component of  claim 16 , wherein the optical component is a housing for an optical sensor that defines an opening for an optical emitter and an opening for an optical detector, wherein the optical pathway is arranged to direct light from the optical emitter through an optical window optically connected to the optical pathway into a fluid sample under analysis and receive light from the fluid sample through the optical window and direct the light to the optical detector. 
     
     
       20. An optical sensor comprising:
 a housing having an optical pathway that directs light through an optical window optically connected to the optical pathway into a fluid sample under analysis and receives light from the fluid sample through the optical window; 
 an optical emitter that is positioned to emit light into the optical pathway; and 
 an optical detector that is positioned to receive light from the optical pathway, 
 wherein the housing is formed of metal and a surface of the housing defining the optical pathway is optically blackened with a metal selenide and emits weaker fluorescent radiation than fluorescent radiation emitted by the fluid sample under analysis in response to exposure to ultraviolet light. 
 
     
     
       21. The optical sensor of  claim 20 , wherein the surface of the housing defining the optical pathway does not emit fluorescent emissions in response to being exposed to light within a wavelength from 250 nanometers to 600 nanometers. 
     
     
       22. The optical sensor of  claim 20 , wherein the metal is copper and the optical component is fabricated from aluminum or stainless steel. 
     
     
       23. The optical sensor of  claim 20 , wherein the surface is not anodized and is devoid of a coating containing organic molecules.